This invention relates to an armature assembly support pallet used for conveying a partly constructed electric motor armature assembly during manufacture.
During manufacture of electric motor armature assemblies having cores made from a stack of laminations, partially manufactured armature assemblies may be supported on support pallets conveyed by a conveyor between manufacturing stations. At one or more of the manufacturing stations, a partially manufactured armature assembly is removed from the pallet for processing by armature handling mechanisms that may include an elevator or a pick and place mechanism, and returned to the same pallet or to an essentially identical pallet by the same handling mechanisms. The handling mechanisms must be capable of transferring the armature assemblies to the processing machines in precise positions or orientations in order to be handled by the processing machines. To simplify the tasks of the handling mechanisms, an armature assembly is positioned on a conveyor pallet in a relatively accurate location. The transverse position of an armature assembly on a pallet is generally maintained by V-shaped supports that support opposite ends of a shaft forming part of the armature assembly. However, the pallets are usually so constructed that the armature assembly can be slightly displaced, on the order of one-sixteenth of an inch or so, in the axial direction of the armature shaft. Thus, the precise axial position of the armature assembly on a pallet is not maintained. Maintenance of an armature assembly location on a pallet within about one-sixteenth of an inch is usually satisfactory and will not prevent proper processing of the armature assembly. However, carefully machined stops and other devices are often needed to hold the location of an armature assembly on a pallet within tolerance.
Electric armature assemblies have many different parameters, such as different shaft lengths, different commutator constructions or locations on their respective shafts, or different lamination stack lengths or locations on their respective shafts. A given pallet may be dedicated for use in conveying an armature assembly of only one configuration so that different pallets will have to be provided for use with armature assemblies having different configurations. Some pallets are not so limited but are provided with readily changeable armature shaft supporting members or with adjustable, i.e., axially movable and/or rotatable, armature shaft supporting members so that the pallets are usable with a wider range of armature constructions. Examples of pallets with adjustable supporting members are described in U.S. Pat. Nos. 5,346,058 and 5,348,142. These same patents show relatively complex pallets and mechanisms for adjusting the positions of the armature shaft supporting members on the pallets.
An object of this invention is to provide an inexpensive armature support pallet by which an armature assembly being manufactured may be maintained in a fixed axial position on the pallet while being conveyed from one workstation to another workstation.
Another object of this invention is to provide an inexpensive armature support pallet which is usable with armature assemblies having a substantial range of different armature configurations. More specifically, an object of this invention it to provide such a pallet which requires no changes or adjustments in order to handle armatures of different configurations. Accordingly, an armature support pallet in accordance with this invention can be used in various different armature manufacturing lines without requiring any initial set up time. If a manufacturing line is changed over from the manufacture of one armature to a different armature, the same pallet can be used, without changes or adjustments, within a large range of various different armature configurations.
In accordance with this invention, an armature assembly support pallet has a body member and a pair of mutually-spaced support assemblies mounted on the body member. The support assemblies support spaced-apart portions of an armature shaft. Each of the support assemblies includes a support member having upwardly-facing, shaft-engaging support surfaces. The support surfaces exhibit magnetic fields so that the portions of the armature shaft adjacent the support surfaces are magnetized and thereby magnetically attracted to the support surfaces.
Preferably, each of the support surfaces which exhibits a magnetic field is formed from a layer of magnetic material secured to its respective support member. In addition, the body member may have an aperture formed therein to provide access from beneath the pallet to an armature assembly carried on the pallet. If the pallet has such an aperture, the support assemblies are preferably mounted on the body member adjacent respectively opposite margins of the aperture. Also, known pallets, including those with adjustable support assemblies, may be modified or retrofitted by securing magnetic material to some or all of their support surfaces.